Many medical procedures used today require some method of airway management. Examples of such procedures include general anesthesia/intubation, mask anesthesia, regional anesthesia/sedation with O.sub.2 supplementation, and semi-surgical and radiologic procedures. Many patients die unnecessarily due to an inability to ventilate or the difficulty encountered during endotracheal intubation. Endotracheal intubation and other methods of airway management are especially difficult to perform on a premature or full-term infant.
Successful airway management requires aligning the oropharyngeal, laryngeal and tracheal axes of the head and neck such that a straight, unobstructed airway passage is formed between the mouth and the larynx. The positioning of the oropharyngeal, laryngeal and tracheal axes is commonly known as the "sniffing position" and has been determined to be the most effective position for improved airway patency and endotracheal intubation.
While achievement of the sniffing position for an adult is difficult for even a skilled anesthetist, achievement for an infant is even more difficult given several anatomic differences relative to an adult. Some of these differences include a large tongue, a high glottis, a narrow cricoid ring and a large occiput. For an adult, the sniffing position is achieved by elevating the head about 10 cm with a pad or towel placed beneath the occiput (shoulders remaining on the supporting surface), flexing the neck and extending the head at the atlanto-occipital joint, either by tilting the head backward with one hand or by pulling up on the mandible or lower jaw bone. Such a technique for achieving the sniffing position in an infant is, however, ineffective. The large tongue of the infant occupies a large amount of space in the infant's airway thus obstructing the infant's airway passage. Additionally, the infant's glottis is located at the level of the fourth cervical vertebra, whereas in the adult the glottis is located at the fifth cervical vertebra Thus, an infant's airway passage is funnel-like in shape in comparison to an adult's, and is quite narrow due to the underdevelopment of the cricoid ring. Perhaps the most significant hindrance to airway patency for an infant is the relatively large size of the infant occiput. The occiput of an infant is somewhat larger than an adult's and results in the infant's head being flexed forward onto the its chest when the infant is lying in the supine position. Thus, when the infant is in the supine position, and the occiput flexes the infant's head forward onto its chest, the oropharyngeal, laryngeal and tracheal axes are naturally misaligned. To overcome the large occiput factor, a properly dimensioned support must be placed beneath the infant's atlanto-occipital joint, hyperextending the neck to align the oral, laryngeal and tracheal axes. Thus, the infant's head and body are lying in substantially the same horizontal plane to achieve the sniffing position.
Maintaining a stable sniffing position in an infant is also difficult due to the infant's inability to remain in a completely still position for long periods of time. The slightest change in head or body position can cause a major change in the position of an endotracheal tube, for example, which could eventually result in extubation. Thus, some type of device is required to restrain the infant, once its head and body are disposed in the proper position for airway management. Additionally, the infant must sometimes remain in the sniffing position for a long period of time, and a support surface which provides comfort and support to the infant resting thereon is beneficial.
Support cushions or devices for use during surgical procedures are well-known in the prior art.
One example is found in the Watson patent (U.S. Pat. No. 4,259,757) which discloses a support cushion for maintaining a patient's head in the proper position for endotracheal intubation, as well as during other medical procedures. A 7.degree. inclination in the cushion allows the oropharyngeal, laryngeal and tracheal axes of the patient to be aligned when the head is correctly positioned within the depression provided in the cushion. The cushion disclosed in the Watson patent is constructed in accordance with the anatomical features of an adult head. Thus, this cushion would be ineffective in aligning the airway axes of an infant given the infant's relatively large occiput and the other alignment inhibiting anatomical factors discussed above. Furthermore, the Watson patent provides no neck or body support to ensure that the sniffing position is maintained once it is achieved.
Another example is the Clark patent (U.S. Pat. No. 4,757,811) which discloses a self-contained infant restraining device used for emergency treatment on a patient of up to two years old. The device includes a head receiving indentation, a body receiving indentation and a plurality of restraining belts. Although the head indentation allows the head of an infant to be tilted backward below the level of the body into a slightly flexed position for intubation, the position afforded by this device is ineffective for successful intubation of an infant. When an infant is disposed upon the device disclosed in the Clark patent, the infant's head and body lie in two different horizontal planes and the infant's head must be further manipulated to achieve the sniffing position.
The Summer patent (U.S. Pat. No. 4,768,246) discloses an apertured head pillow which does allow the user's head and body to rest generally in the same horizontal surface. However, the device of the Summer patent is not directed to a support for airway management of an infant and does not provide the required neck support to perform the same. Furthermore, the device does not provide a means for restraining the infant's head and body to prevent movement which could dislocate an endotracheal tube, for example, or cause extubation.
Although the Dixon patent (U.S. Pat. No. 4,320,543) discloses a pillow to provide support for the head and neck of the user which incorporates a convoluted upper surface for support, it does not provide a means for aligning the axes of an infant's airway given the special anatomical features of an infant. Thus, the advantages of the present invention are not found in the prior art.